In the case of capturing an image by using an image-capturing apparatus such as a digital camera in a poor image-capturing environment such as a dark environment where illuminance is relatively low or backlit, image quality deterioration may occur. For example, in the case of setting a long exposure time in order to secure a sufficient exposure time and performing capturing, a motion blur phenomenon due to a long shutter speed, shaking of an image-capturing apparatus, or motion of an object may occur. Also, in the case of setting sensitivity of a camera to high sensitivity and performing capturing, a dark image is amplified together with a noise component, so that a large amount of noise may appear on an image on the whole.
To resolve an image quality deterioration problem of an image captured in such a low illuminance environment, technology for removing motion blur based on one resultant image sheet, high performance noise-removing technology, etc. have been developed. Recently, technology for blending and processing a plurality of images, rather than just one image sheet is under development.